Strap feeding device



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rf/500056 0. SN/DEE "Y www? 'H/s /JrTE/VEYS United States Patent O 3,150,586 STRAP FEEDING DEVICE Theodore 0. Snider, Dayton, Ohio, assigner, by mesne assignments, to Signode Steel Strapping Company, Chicago, Ill., a corporation of Delaware Filed Oct. 17, 1961, Ser. No. 145,704 11 Claims. (Cl. 10D- 25) This invention relates to a strap feeding mechanism and more particularly to what is known asv a bayonet strap feed mechanism useful in compression strapping machines, although not necessarily so limited.

An object of this invention is to provide an improved bayonet strap feed device driven by an electric motor.

A further object of this invention is the provision of means to control a bayonet drive motor through movement of the bayonet.

Still another object of this invention is the provision of improved gripper structure mounted upon the bayonet adapted to engage and clamp a strap thereto.

Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture and the mode of operation, as will become more apparent from the following description.

Referring to the drawings:

FIGURE 1 is a perspective view of a compression vstrapping machine provided with a bayonet strap feed device made in accordance with this invention.

FIGURE 2 is a perspective view of a portion of the mechanism enclosed within the arcuate line 2 of FIG- URE l. Part of the strapping machine has been broken away in FIGURE 2 to disclose details of the strap feed mechanism.

FIGURE 3 is a side elevational view, with portions broken away and in section, of the compression strapping machine and the bayonet strap feed device made in accordance with this invention.

FIGURE 4 is a sectional view of a bayonet used to engage and move a strap taken along line 4--4 of FIG- URE 5.

FIGURE 5 is a plan View of the forward portion of the bayonet.

FIGURE 6 is a side 'elevational view of the forward portion of the bayonet.

FIGURE 7 is a front elevational view of the forward portion of the bayonet.

FIGURE 8 is a cross sectional view of a strap guide or chute taken along linesl 8-8 of FIGURE 3.

In FIGURE l, a bayonet strap feeding device, generally designated 10, is shown as mounted adjacent the rear of a platform 12 of a compression strapping machine, generally designated 14. If desired, there may be several bayonet devices 10 located side-by-side behind the platform 12. The platform 12 comprises Aa base 16 upon which are mounted, by brackets 18, a plurality of conveyer rollers 20. A turntable mechanism 22, mounted centrally of the platform 12, may be used to permit the operator of the strapping machine to rotate a load placed on the strapping machine. The operation of the turntable mechanism forms no part of this invention and accordingly is not described herein.

The compression strapping machine 14 is designed to be positioned in a conveyer system wherein the load 'to be strapped is rolled onto the platform 12. When on the platform, a press platen 24, which is mounted for vertical sliding movement on a pair of upright posts 26 and actuated by hydraulic or pneumatic actuators 28 supported thereon, is lowered onto the load. While the load is under compression, it is encircled -by a strap clamped thereto by a strapping device schematically illustrated at 30. The details of the device 30 may be entirely conventional and form no part of this invention.

lCC

To encircle a load, a strap 32 driven by a drive motor 44 is coursed through an upper guide 34 mounted on top of the platen 24 through a second guide 36 mounted internally of the platen 24 to a rear guide or chute 38 which projects vertically at the rear of the platform and, linally, to a platform guide 40 extending horizontally through the platform 12. The strap 32 may be coursed through the various guides 34 through 40 before the load is placed under compression or while the load is under compression. After the strap is coursed through the various guides, the end of the strap projecting forwardly of the platform guide 40 is placed within an aperture in the strapping machine 30 while a portion of the strap projecting forwardly of the upper guide 34 is similarly placed in the strapping machine 30. The strapping machine then clamps or fastens these two straps together.

The lower guide 40 may include pivoted guide members 42 (FIGURES 2 and 3) which are spring loaded to retain the strap beneath the upper surface of the platform 12. When the end of the strap is pulled upwardly to the strapping device 30, the guide members 42 are pivoted out of position whereupon the strap is released from the guide 40. The guide 40 functions in a manner similar to the member 38 shown in cross section in FIGURE 8. Member 3S includes a vertical post 43 to which an angle bracket 43a is affixed. A pivoted guide member 45 is welded to a plate 45a pivotally mounted upon the bracket 43a by a pin 47. A spring 47a coiled about the pin 47 biases the member 45 into the position shown in FIG- URES 3 and 8, wherein a channel to receive the strap 32 is formed between the forward portion of the member 45 and the post 43. Should the strap be pulled to the right, as Viewed in FIGURES 3 and 8, the bias of the spring 47a is overcome, whereupon the strap is released from the guide. The details of the strap drive mechanism and the guides therefor are not more fully illustrated herein since such structures are old and well known inthe art. In fact, up to this point, the structure described herein may be entirely conventional.

Oftentimes it is desired to strap a load to a pallet. For this purpose, pallets are often provided with apertures or channels through which the strap is to be coursed. Such a pallet, designated 46, is shown in cross section in FIGURE 3 and comprises upper and lower plates 46a, 46b held in spaced relation by ribs 46c. There may be several spaced ribe 46c providing a plurality of longitudinally extending apertures between the plates 46a and 4612. Further, the ribs may be so designed as to provide a plurality of transversely extending apertures in the pallet 45. Rather than course the strap around the load and the pallet 45, the strap or straps extend around the load and through :the longitudinally extending apertures in the pallet 46. When coursing a strap through an aperture in a pallet, the strap guide 40 obviously could not be used.

Various types of strap feeding devices have been developed especially for coursing straps through pallets.

In accordance with this invention, the type of strap feeding device used for coursing the strap through a pallet is the bayonet device 10, and this invention is directed to an improvement in the construction and operation in the bayonet strap feeding device.

Referring to FIGURES 2 and 3, the bayonet strap feeding device includes a generally rectangular elongate bayonet 48 including a gripper head 50 adapted to grip an end portion of the strap 32 as will be described below. The bayonet 48 is mounted for sliding movement, along an axis transverse lto the longitudinal axis of the chute 38, between a pair of plates 52, 54 which are mounted upon the rear of the platform 12. A plurality of vertically oriented guide rollers 56 are mounted by brackets 58 between the plates 52 and 54 and provide support for the bayonet 48. In addition, nylon pads or other suitable non-conductive, low-friction bearing material (not shown) may be applied to the internal sides of the plates 52, 54 in engagement with the bayonet 48 so that the bayonet 48 is confined by the guide rollers 56 and the bearing material mounted internally of the plates 52, 54.

The bayonet 48 comprises a generally hollow, rectangular tubular body member 60, which may be made from metal or any other suitable material, enclosed at its rearward end by a cap 62 made from insulating material such as a synthetic plastic. As shown best in FIGURES 2 and 4, the rear cap 62 has a centrally located body portion projecting internally of the hollow body member 60 and an enlarged, generally rectangular portion projecting rearwardly of the body member 60. The cap 62 is aflixed to the member 60 as by screws 64. The forward portion of the bayonet 48 is provided with a cap 66 retained thereon by a pair of screws 68. The cap 66 is also made of a suitable insulating material and is similar in construction to the cap 62 but further includes a pair of forwardly projecting flanges 70 and 72 (FIGURE which provide a support for and conne the gripper head 50, as will be described more fully below. The portions of the caps 62 and 66 projecting beyond the ends of the body member 60 are enlarged or slightly wider than the body member 60 to serve as stops for limiting the movement of the bayonet.

The bayonet 48 is provided with electric circuit conducting elements used in the control of the bayonet drive. To this end, the internal portion of the caps 62, 66 are bored to provide centrally located recesses 62a, 66a communicating with the hollow internal portion of the body member 60. A pair of conductor elements in the form of contact screws 112, 150 project from the lower surface portion of the caps 66, 62, respectively, into the recesses 66a, 62a. The screws 112, 150 are engaged with the opposite ends of an insulated conductive wire 116 which is enclosed within the recesses and the hollow portion of the body member 60. The screw 112, in turn, is electrically connected to the gripper head 50 by means of a contact spring 110 affixed to the cap 66 by the screw 112.

As shown in FIGURES 4 through 7, the gripper head 50 comprises a pair of gripper jaws 84 and 86 apertured to receive a pivot pin 82 held, as by set screws 83, within coaxial apertures 80 in the anges 70, 72. For convenience, the jaw 84 is termed an internal jaw, while the jaw 86 is termed an external jaw. The internal jaw 84 is generally rectangular, but has a rounded upper cam surface portion tapering downwardly to a plurality of teeth 96 cut in its forward face. The external jaw 86 is generally T-shaped, as viewed from above, including a leg portion 86a through which the pin 82 projects and a generally rectangular head portion 86b overlying the jaw 84 and the flange 70.

A coil spring 88 wrapped around the pin 82 internally of a cup-shaped aperture formed in one side of the jaw 84 biases the jaws 84, 86 into a relative position wherein the internal surface of the head portion 86h is in intimate contact with the teeth 96. One end of the spring 88 projects into a well or recess 92, cut internally of the jaw 84, while the other end of the spring 88 is bent to project into a well or recess 94 cut within the contiguous side of the external jaw 86 so as to be substantially coplanar with but laterally spaced from the recess 92. The two jaw members 84, 86 in turn are both biased relative to the ange 70 by means of a wire spring 98 which projects through a channel 100 cut in the side of the jaw 86 adjacent the flange 70. The lower end of the spring 98 projects into an aperture cut in the ange 70, while its upper end bears against the head portion 86h of the jaw 86. The spring 98 thus biases the gripper head 50 in a clockwise direction, as viewed in FIGURE 6. A rearwardly projecting shoulder 86e` on the jaw head 86b 4 engages the forward wall of the flange 70, whereupon the jaws 84, 86 are biased into the position illustrated in FIGURES 4 through 7, wherein the teeth 96 project forwardly while the head 86b projects vertically.

When not in use, the bayonet 48 occupies the position shown in FIGURE 3, wherein the gripper head 50 lies slightly behind the guide 38. The strap 32 accordingly normally passes through the guide 38 into the guide 40 in the platform 12. However, the guide 38 and the guide 40 are spaced to provide a gap therebetween through which the bayonet 48 may project. If it is desired to use the bayonet 48, the operator of the strapping machine closes a switch (not shown) which actuates a solenoid 118 mounted upon the plate 54. The solenoid 118 is directly connected to a link 120 which has a roller 122 mounted on its upper end. The roller 122 engages a cam surface 124 and a link 126 which is pivoted at its lower end to the plate 54 and held in a normally vertical position by means of a spring 128 mounted on a bracket 130 supported on the plate 54. A starter pin 132 is attached to the top of the link 126 and projects into an aperture 134 in the plate 54 immediately behind the enlarged portion of the cap 66. Upon actuation of the solenoid 118, the roller 122 moves vertically upwardly against the cam surface 124 whereupon the bias of the spring 128 is overcome. The link 126 accordingly is pivoted in a counterclockwise direction as viewed in FIGURE 3. In turn, the pin 132 presses against a shoulder portion 136 (FIGURE 5) of the cap 66 to move the bayonet 48 forwardly by a short distance. The gripper 50 then projects vertically beneath the guide 38. As noted before, the gripper jaw 84 has a rounded upper surface. The head portion 86h of the jaw 86 is bevellcd along the top of its internal surface. The internal surface of the head 86b and tne forward portion of the jaw 84 thus cam or guide the strap 32 to the point of engagement of the cooperating gripper surface portions formed by the teeth 96 and the internal portion of the head 86b. The strap is suiliciently strong that, when it engages the rounded upper surface of the jaw 84, it cams the cooperating gripper surface portions of the jaw members 84 and 86 apart by an amount sufficient to receive its forward end. Thus, the action of the strap being cammed between the jaw members 84 and 86 overcomes the bias of the spring 88 which tends to hold the gripper portions of the two jaw members together.

As shown in FIGURES 3 and 4, a contact spring 140 is mounted upon the platform 12 beneath the bayonet and slightly to the right, as viewed in FIGURES 3 and 4, of the chute 38. When the bayonet 48 is initially driven to the left upon operation of the solenoid 118, the contact screw 112 contacts the spring 140. The contact spring 140 is connected through suitable circuitry (not shown) to a relay (not shown) used to operate a reversible motor 142 mounted upon the plate 54. The reversible motor 142 is connected through gears in the gear housing 144 to a friction drive wheel 146 frictionally engaged with the top surface of the bayonet 48. The circuit for reversing the reversible motor 142 is such that the motor shaft rotates in a forward direction, that is, in a direction to move the bayonet forwardly, or to the left, as viewed in FIGURE 3, when the contact member 140 is connected to ground. When the contact member is first engaged with the contact screw 112, no ground connection is effected because the bayonet 48 is insulated by the non-conductive guide rollers 56 and the nonconductive bushings mounted on the internal surfaces of the plates 52 and 54. Note, however, that the contact screw 112 is electrically connected by the contact spring 110 to the gripper jaw 84. When the strap 32 initially engages the gripper head 50, the contact spring 140 is then connected through the screw 112, the contact spring 110, the gripper head 50 and the strap 32 to ground. Accordingly, the motor 142 is energized to move the bayonet to the left, as viewed in FIGURE 3, when the strap 32 iirst engages the gripper head 50.

Upon energization of the motor 142, the bayonet 48 is rapidly moved to the left, as viewed in FIGURE 3, into the position indicated by phantom lines 48a and 50a. Upon such movement of the bayonet 48, the strap 32 is threaded through the aperture in the pallet 46. The bayonet 48 is driven more rapidly than the feed mechanism which ordinarily feeds the strap. Accordingly, the strap is forcefully removed from the guide chute 38. The resistance provided by the springs 47a, tending to retain the strap within the chute 38, overcomes the bias provided by the spring 98. The gripper jaws 84 and 86 accordingly rotate in a clockwise direction, as viewed in FIGURE 3, about the pin 82, so that the end of the strap 32 clamped by the jaws 84 and 86 does not project vertically when carried through the pallet 46, but, rather, extends at an angle to the vertical, as shown at 32a. This angle is on the order of 45 and is such that the end of the strap 32a is on a line directed upwardly toward the guide 38. There is thus no danger that the strap will be damaged by ystriking the pallet as it is coursed therethrough.

The bayonet moves forwardly until the enlarged stop portions of the cap 62 strike the rearmost edges of the plates 52 and 54. A contact spring 148 is mounted rearwardly of the plates 52 and 54. When the bayonet 48 reaches its extreme forward position, that is, the position to the left, as viewed in FIGURE 3, a contact screw 150 mounted in the rear lcap of the bayonet 48, and electrically connected to the rearward end of the conductive wire 116, engages the contact member 148,whereupon the motor 142 is deenergized. The motor remains deenergized until the strap 32 is removed from the gripper head 50. When this occurs, the ground connection of the contact spring 148 through the screw 150, the conductive wire 116, the screw 112, the contact spring 110, the gripper head 50 and the strap 32 is broken. The motor 142 is then reversed, whereupon the friction wheel 146 drives the bayonet 48 rearwardly or to the right, as viewed in FIGURE 3. The bayonet 48 continues its rearward movement until the stop portions of the cap 66 engage the forward edge of the plates 52 and 54. At the same instant, a microswitch or limit switch 152 drops in a depression 154 in the top of the body portion 60 of the bayonet 48. The limit switch 152 serves to disable the motor circuit. The operation of the bayonet 48 is thus completed. Of course, when the strap 32 is removed from the gripper head 50 by the operator of the strapping machine, the operator places the strap 32a into the strapping or clamping device 30 to complete the strapping of the load.

It will be appreciated that the bayonet drive mechanism provided by the reversing motor 142 and its associated friction wheel 146 constitutes a Very simple but reliable drive for the bayonet 48. The control of the movement of the bayonet 48 is further simplified by providing the conductor member 116 projecting through the bayonet 48 which is engaged by the contact member 148 to control the circuit for the reversing motor 142. Importantly, the control of the movement of the bayonet 48 depends upon the engagement of the strap 32 with the gripper head 50 in order to connect the various contacts to ground. Thus, the drive of the bayonet 48 is completely automatic once the drive is initiated. Since the circuitry for the reversing motor 142 may be entirely conventional, and such circuits are well known, it is not described in detail herein. Such a circuit, for example, could utilize a holding relay which is initially energized when the Contact spring 140 is connected through ground as the forward end of the strap 32 engages the gripper head 50. The holding relay could keep the motor circuit closed until the contact member 148 engages the contact screws 150, at which time the bayonet has reached its forwardmost position. Upon removal of the ground connection provided by engagement of the strap 32 with the gripper head 50, the reverse circuit for the motor 142 could be closed and remain closed until the limit switch 152 engages the depression 154 in the bayonet 48. When the cycle of movement of the bayonet 48 is completed, it is prepared for another cycle of movement. Thus, the operator need only initiate operation of the solenoid 118 to move the bayonet 48 forwardly into position to receive another portion of the strap 32. Upon this forward movement of the bayonet 48, the limit switch 152 rolls out of the depression 154 and does not operate until the bayonet 48 is again returned to its rear- -most position indicated by the full lines in FIGURE 3.

Although the presently preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and dened in the appended claims.

Having thus described my invention, I claim:

1. In a strapping device wherein a strap is guided along a guide chute, the combination comprising: a bayonet including a body member having a gripper head mounted thereon; means slidably supporting said bayonet for movement along an axis angularly displaced from the chute; iirst drive means positioning the gripper head adjacent the chute in position to receive a strap passing through said chute; and second drive means responsive to engagement of the strap with the gripper head for driving the Vbayonet along said axis to pull the strap away from the chute, said second drive means including an electric motor and a friction disc driven by said motor engaged with said bayonet.

2. In a strapping device wherein a strap is guided along a guide chute, the combination comprising: a bayonet including a body member having a gripper head mounted thereon; means slidably supporting said bayonet for movement along an axis angularly displaced from the chute; first drive means positioning the gripper head adjacent the chute in position to receive a strap passing through said chute; and second drive means responsive to engagement of the strap with the gripper head for driving the bayonet along said axis to pull the strap away from the chute, said gripper head comprising iirst and second gripper jaws having cooperating gripper surface portions, means interconnecting said jaws biasing said surface portions into intimate contact, at least one of said jaws having a cam surface portion adapted to direct a strap into engagement with said gripper surface portions, said bayonet further including support means rotatably supporting said gripper jaws, and bias means biasing said jaws relative to said body member into a position wherein said gripper surface portions are oriented to receive a strap.

3. For use in a strapping device, a bayonet comprising: an elongate tubular body member; a pair of insulating caps, one mounted at each end of said body member; a gripper head including a pair of gripper jaws supported on one of said caps; a pair of conductor elements, one projecting from a surface portion of each of said caps, and a conductive wire extending through said body member interconnecting said conductor elements.

4. The structure of claim 3, wherein a further conductor element electrically connects one of said aforementioned conductor elements to the gripper head.

5. The structure of claim 3, wherein said gripper head comprises first and second gripper jaws mounted for relative rotation on one of said caps, said jaws having cooperating gripper surface portions, bias means interconnecting said jaws biasing said surface portions into intimate contact, cam means formed on at least one of said jaws adapted to guide a strap into engagement with said gripper surface portions, said bias means being overcome 7 by engagement of a strap with said surface portions whereupon said strap causes said portions to separate by an amount suiicient to receive said strap.

6. In a strapping device of the type having a guide chute through which a strap is coursed, a strap feed mechanism comprising: a bayonet including an elongate hollow tubular body member, a pair of insulating caps one mounted at each end of said body member, a gripper head including a pair of gripper jaws supported on one of said caps, conductor means projecting through said body member and said caps, and a conductor element electrically connecting said conductor means to the gripper head; means slidably supporting said bayonet for movement along an axis angularly offset from the chute; first drive means positioning the gripper head adjacent the chute in position to receive a strap; and second drive means responsive to engagement of a strap with the gripper head for driving the bayonet along said axis away from the chute.

7. The structure of claim 6, wherein said second drive means includes an electric motor and a friction disc driven by said electric motor engaged with said bayonet.

S. The structure of claim 6, wherein the gripper head comprises rst and second gripper jaws mounted for relative rotation on one of said caps, said jaws having cooperating gripper surface portions, bias means interconnecting said jaws biasing said surface portions into intimate contact, cam means formed on at least one of said jaws adapted to guide a strap into engagement with sid gripper surface portions, said bias means being overcome by engagement of a strap with said surface portions where- 8 upon said strap causes said portions to separate by an amount sucient to receive said strap.

9. In a strapping device wherein a strap is guided along a guide chute, the combination comprising: a bayonet including a body member having a gripper head mounted thereon; means slidably supporting said bayonet for movement along an axis angularly displaced from the chute; and drive means for driving the bayonet along said axis including an electric motor and means driven by said motor engaged with said bayonet.

10. The structure of claim 9 wherein said means engaged with said bayonet comprises a friction disc.

11. For use in a strapping device, a bayonet comprising: a body member; a gripper head, said gripper head including rst and second gripper jaws having cooperating gripper surface portions and means interconnecting said jaws biasing said gripper surface portions into intimate contact; suppor means rotatably supporting said gripper jaws on said body member; and bias means biasing said jaws relative to said body member.

References Cited in the file of this patent UNITED STATES PATENTS 217,224 Johnson July 8, 1879 1,693,728 Rainsford Dec. 4, 1928 1,784,025 Norton Dec. 9, 1930 2,612,833 MacChesney Oct. 7, 1952 2,629,316 Tillinghast Feb. 24, 1953 2,754,117 Ghormley July 10, 1956 2,780,986 Ritenour Feb. 12, 1957 2,985,098 Winkler May 23, 1961 

1. IN A STRAPPING DEVICE WHEREIN A STRAP IS GUIDED ALONG A GUIDE CHUTE, THE COMBINATION COMPRISING: A BAYONET INCLUDING A BODY MEMBER HAVING A GRIPPER HEAD MOUNTED THEREON; MEANS SLIDABLY SUPPORTING SAID BAYONET FOR MOVEMENT ALONG AN AXIS ANGULARLY DISPLACED FROM THE CHUTE; FIRST DRIVE MEANS POSITIONING THE GRIPPER HEAD ADJACENT THE CHUTE IN POSITION TO RECEIVE A STRAP PASSING THROUGH SAID CHUTE; AND SECOND DRIVE MEANS RESPONSIVE TO ENGAGE- 